Research on the Settlement Behavior of Ram-Compacted Piles with Bearing Base

In order to study the settlement characteristic of ram-compacted piles with bearing base (RPBB), pile-raft composite foundation in high-speed railway, RPBB, and Cement Fly-ash Gravel (CFG) piles were tested and compared under the Beijing-Shanghai high speed railway. Using hydrostatic levels, the settlements of test sections were monitored over the long term. Results show, because of the formation conditions and the construction technology of RPBB, the reinforced depth of RPBB is limited. Consequently, the settlement of RPBB is bigger than CFG. It also takes longer to reach stable settlement for RPBB. In addition, based on measured and modified soil compression modulus, the thicknesses of compressed layers and the settlements were calculated using control strain method and control stress method. The calculated results using control strain method and modified soil compression modulus are reasonably close to the testing data. This proves that the modified soil compression modulus can improve the precision and reliability of the settlement estimation. This can overcome the limitations of existing Chinese code.